WSClean version 2.9

Released 2020-03-27

WSClean 2.9 is released together with IDG version 0.7.

Summary of changes: WSClean+IDG is now much faster, in particular with fast-changing aterms. The combination of WSClean 2.9 + IDG 0.7 supports the efficient use of GPUs to grid large data volumes with complex a-terms. Furthermore, a new gridder that is more accurate compared to the default w-stacking gridder, and for some cases also faster! (in particular large images, many visibilities). The plan is also to move WSClean to Github in the next version of thereafter.

Major & visible changes:

  • Add new gridder “wgridder”, a stand-alone gridder written by Martin Reinecke that is now integrated in WSClean.

  • Applying a second aterm to all antennas is possible by setting dimension of antenna axis to one in aterm fits file.

  • Make source list output possible in IDG.

  • The FFTs are now performed with floats instead of doubles, thereby descreasing memory usage by 2 and increasing the speed anywhere from 20-100%.

  • LOFAR image-based beam correction (i.e. no aterm correction) now uses full Mueller matrix calculations instead of Jones, which removes some biases in beam correction that were seen.

  • New options -reuse-psf and reuse-dirty to skip these steps when they already exist.

  • WSClean makes use of IDG’s API changes to allocate optimal buffer sizes, greatly increasing the speed of IDG, and solving allocation problems on low-mem platforms

  • When parallel deconvolution is used, the logging is now much improved: only one thread reports its full progress.

  • Correct smallest multi-scale scale when using Gaussian tapering. Multi-scale cleaning was using just the longest baseline for determining the smallest scale to clean with. This causes tapered imaging to almost never use the smallest scale.

  • Add a ‘dry run’ mode, requested by J. Morgan. Fixes #162.

Bug fixes & other changes:

  • Stokes V imaging with R/L pols results in zero image (reported by Chiara Stuardi)

  • Don’t allow direct MS access for multi spw sets, to prevent a deadlock.

  • Output error when trying to combine parallelgridding with IDG.

  • Don’t incorrectly apply the average beam when using idg + apply-primary-beam.

  • Support newer casacore versions.

  • Remove dependency on boost thread.

  • Image the gridding kernel as option was removed, as both IDG and WGridder don’t support it.

  • Fix beam calculation for 1 timestep mses

  • Fix a crash when using pb correction + deconvolution channels

  • Solve reported problem with HDF5/Intel compilation